The storm that gets you is never the one you watch. It builds somewhere west of the river in the afternoon, drops an inch of rain in twenty minutes, and knocks the lights out for a second on its way past Prairieville. Then the power comes back and the house has a new problem. The air conditioner control board is dead. The refrigerator runs but its display is blank. The garage door opener clicks and does nothing.
Most people call that a lightning strike. It usually is not one, not in the way they mean.
What actually kills the electronics
A direct hit on your roofline or chimney is rare, and when it happens the damage is obvious to everyone, including your insurance company. What takes out appliances across a whole neighborhood is the strike that lands somewhere else. It hits an overhead utility line, a transformer on a pole, or wet ground a few hundred feet from your house, and the energy it dumps into the grid rides the service conductors into your panel as a voltage spike. Utility switching gear does a smaller version of the same thing when it reroutes circuits during a storm.
Louisiana is one of the most lightning prone states in the country. Vaisala, which runs the network most utilities and researchers use to count strikes, puts it in the top five by density, and that count includes cloud to cloud strikes along with the ones that reach the ground. So this is not a hypothetical problem here. It is a seasonal one.
The strike itself is over in microseconds. The spike it sends down the wire is not. It arrives at your panel looking for a path to ground, and on the way it crosses the wiring inside your walls, where every device with a microprocessor in it looks like a road.
This is what goes first in a house after a close storm:
- Inverter driven HVAC compressor boards and the ECM blower motors that go with them
- The logic boards inside refrigerators, induction ranges, and dishwashers
- Control modules on tankless gas and hybrid electric water heaters
- Smart home bridges, motorized gates, and network switches
A power strip does not stop any of it. The joule number printed on the box is not much help either. NEMA's surge protection group says comparing energy ratings between devices is misleading and that reputable makers have stopped publishing them, which is worth remembering the next time a package advertises an enormous number next to the word joules.
Type 1 and Type 2, and what the code actually says
Panel mounted surge protection lives in NEC Article 242, and it comes in two kinds that get confused constantly.
A Type 1 device is listed for the line side of your main service disconnect, between the utility transformer and the main breaker, so it takes the hit before current enters the panelboard at all. It is also permitted on the load side, which surprises people.
A Type 2 device is the residential answer. It mounts inside or beside your main panel and wires into a dedicated double pole breaker, with its leads bonded to the neutral bus and the equipment grounding system. It clamps what gets past the meter, and it also absorbs the surges your own equipment makes when big inductive loads cycle, which around here means pool pumps, AC compressors, and shop tools. A Type 2 cannot go on the line side of the service.
Louisiana requires a surge protective device on new one and two family services. That requirement reaches the state through NEC 230.67, adopted under LAC 17:I.115, and the state is explicit about how far it reaches: enforcement is mandatory for new construction, reconstruction, additions to an existing home, and extensive alterations. An existing service nobody is touching is not required to be retrofitted. The 2024 I-Codes and the 2023 National Electrical Code were both approved by the state's code commission on July 7, 2026 and take effect January 1, 2027, so the baseline is about to move rather than having already moved. Nothing in an older house is out of compliance, and nobody is coming to inspect it.
Where the install gets decided: lead length
Inside a good SPD is an array of metal oxide varistors. At normal line voltage each one sits at very high resistance, close to a billion ohms, which makes it effectively an open circuit. When a transient pushes the voltage past the clamping level, the varistor turns highly conductive and sends that energy down the grounding conductor instead of through your kitchen.
That transition happens in a hurry, which is exactly why the wiring to the device matters more than the spec sheet does. The let through voltage a protector is rated for is measured in a lab with six inch leads. Every extra foot of conductor between the device and the panel adds something like 100 to 170 volts of let through voltage, and the inductance of a long run slows the device down as well. Long, looped, tidy looking leads are the most common way a correct part ends up doing half its job.
Six inches, straight runs, no sharp bends. There is a wrinkle worth knowing before someone trims those leads to nothing: at least one major manufacturer voids the warranty if the leads are shorter than six inches, so the target is six, not zero. An SPD is only as good as its shortest path to ground, and that is a physical distance, not a setting.
The ground rod is the other half of it
Every joule the SPD shunts goes into the grounding electrode system. If that path is poor, the current finds another way out of the house, and the other way is usually the electronics you were trying to save. NEC 250.53(A)(2) calls for a second rod unless the first one has a resistance to earth of 25 ohms or less. The code does not make anyone measure it, and in practice most electricians skip the test and drive the second rod, because a rod is cheaper than an afternoon with a ground resistance tester.
Questions I get asked
Do I still need the strips at my computer
Yes. Whole home protection works as a cascade. The panel device knocks a large external spike down to something manageable, and a good point of use strip takes the residual off the last few feet before it reaches a laptop or a television. The panel unit is what keeps the event from entering the house in the first place.
Will it survive a direct strike on the house
Probably not, and no honest electrician will tell you otherwise. A direct hit carries enough energy to destroy equipment no matter what is installed. What a good SPD does is sacrifice itself and divert most of that current into the grounding system, which is the difference between replacing a surge module and replacing a house.
How do I know when it is used up
Better units carry indicator lights and sometimes an alarm. The varistors degrade as they absorb surges, so the light goes from green to red when the module has given what it had, and then the cartridge or the whole unit gets replaced. A protector from 2009 with no indicator on it has probably been a paperweight for years.
Does a surge protector fix the flicker when the AC starts
No, and those two problems get confused constantly. A dip every time the compressor kicks on is a voltage drop issue on the circuit or the service, and it needs to be measured rather than filtered. If the sag is coming from the utility side, that call belongs to whoever is named on your bill. Prairieville sits in territory split between DEMCO and Entergy Louisiana, sometimes block by block, so check the bill or the utility's outage map before you dial.
What to do about it
If your house has taken a hit, or you have replaced two control boards in three summers, the useful step is having someone look at the panel and the grounding instead of buying another strip. That means measuring the grounding electrode resistance, checking the panel for heat damage, and confirming that what is installed matches the equipment you are trying to protect. If you want the shorter version of what a panel-mounted unit actually involves, it is laid out on our surge protection page.
That is a morning of work, and it is cheaper than a second compressor board.